Each patient will undergo two intradermal peritumoral injections with a total of 2-3 mCi of unfiltered technetium-99m sulfur colloid in a volume of 1cc, within 24 hours prior to surgery. These injections will take place in the nuclear medicine suite at Rhode Island Hospital under Dr. Richard Noto's supervision. Following the injection of the Tc-99m sulfur colloid a lymphoscintigram will be performed to detect the presence of a sentinel node. Intra-operatively, 5 to 10 minutes prior to the groin dissection, 3 cc of isosulfan blue dye will be injected at the peritumoral edge in a manner and location similar to the Tc-99m sulfur colloid injection. An inguinal dissection will then performed before the radical excision of the vulvar tumor. Prior to the groin node incision, a hand held collimated gamma counter will be used to identify the location of the sentinel node. This area will be marked with ink on the skin surface. An inguinal incision will be made and the inguinal lymphatic beds will be dissected to identify blue afferent lymphatic tracts and/or blue stained lymph nodes. A hand held collimated gamma counter will be used to detect any lymph nodes with increased activity, defined as a count greater than 5 % of that at the injection site, through the groin incision. Also, any lymph node with a blue lymphatic tract leading to it or stained blue will be considered a sentinel node. As well, any lymph node identified with the hand held gamma counter as taking up the Tc-99m sulfur colloid will be considered a hot sentinel node. Each sentinel node will be evaluated with a 10 second gamma count and labeled as hot and blue, hot and non-blue or cold and blue. With completion of the sentinel node groin node dissection, the lymphatic beds will be re-scanned with the gamma counter to ensure all sentinel nodes have been removed. Once the SLN groin dissection is complete the incision will be closed and a full groin dissection will be done at a separate sitting pending the pathologic evaluation of the sentinel lymph node. The remainder of the surgery for the treatment of the primary tumor will then be completed with a current standard of care procedure depending on the size and location of the tumor.